Process for manufacturing amino sulphonic acid



PatentedDec. 14, 1931 UNITED STATES PROCESS FOR MANUFACTURDTG AMINO SULPHONIC ACID Paul Baumgarten, Berlin, Germany, assignmto E. I. du Pont de Nemoum and Company, Wilmington, M, a corporationot Delaware No Drawing. ApplicationJune 30, 1936, Serial In Germany May 21,; 1935 Claims. (01123-9190) My present invention relates to a new process for manufacturing amino sulphonic acid and is based on the observation that this compound is formed when acting with fuming sulphuric 5 acid upon urea.

' When urea is introduced into-fuming sulphuric acid, a strong reaction takes place. with evolution of gas a white crystalline product separates which consists of amino sulphonic acid. Probably, the reaction occurs according to the following scheme":

n that means,-that in the first stage a carbamino sulphonic acid is formed by the action of SO: upon urea. This intermediate product is decomposed by sulphuric acid with formation'of cyanic'acid which is unstable under the said re- 20 action conditions, and of amino sulphonic acid which is insoluble in sulphuric acid and thus is parated.

According to the scheme given above, a similar result is obtained when reacting S: with urea 25 and when treating the reaction product with water or preferably with sulphuric acid.

The examples following hereafter serve to 11- lustrate my invention without limiting it to the specific details given therein. The parts are by so weight it not otherwise indicated. ,J

Example 1.'3 parts of finely pulverized urea are introduced in small portions, while cooling. into 35 parts of oleum containing about 35 per cent. of $03. A violent reaction occurs immedi- 86 ately with evolution of gas which persists forsome time after 'the introduction of the total amount of the urea and which may be completed;

if desired, by warming the mixture on the water bath. Aiter standing for some time, the amino 40 sulphonic acid formed is completely separated and is filtered off with a glass suctioniilter. The

yield is 4.5 parts. After recrystallization from water, the pure amino sulphonic acid, melting at-206" 0., is obtained. A 45 This yield may be essentially improved by mitigating the violence of reaction of urea with oleum, which may be done by a suitable cooling of the oleum and by slowly introducing the urea.

When the reaction mixture then is warmed, the

double decomposition with evolution oi gas and separation of amino sulphcnic acid is brought to an-end. V

On the other hand, urea may be dissolved in sulphuric acid of about 100 per cent. strength with 56 formation of the sulphate; if then oleum with a high content of S03 is added, the reaction is easily completed by warming.

In this manner, the total nitrogen of the urea may be used for the formation of am o sulphonic acid according to the equation: 5

Similar conditions prevail when reacting urea in a first stage with S0: and then treating the reaction compound with sulphuric acid. in.

Example 2.-3 parts of finely pulverized urea are introduced, while cooling with ice, so slowly into 35 parts of oleum containing 35 per cent? of $03, that no violent reaction occurs. The reaction mixture thus obtained is then warmed; with evolution of gas amino sulphcnic acid separates'. 'When the evolution of gas has'cea'sed, the mass is cooled and the amino sulphcnic acidformed is filtered ofi with a glass suction filter.

Example 3.'-3 parts of urea are dissolved, while cooling, in a mixture or 5 parts by volume 01 concentrated-sulphuric acid and 2 parts by volume .of ole containing '70 per cent. of S03. Then 6 parts by volumeof oleum of 7 0 per cent. strength and 5 parts by volume of concentrated g5 sulphuric acid are added and the mixture is warmed. The separated amino sulphonic acid i'ormed with evolution of gas is filtered oflP with; a glass suction filter,'the yield beingabout 9 parts by weight.

1 Erample 4. -Into a cold mixture of 200 parts by volume of concentrated sulphuric acid of 95.6

per cent. strength and 70 parts by volume 0? oleum containing 70 per cent. of S03, 60 parts of urea are introduced while stirring and cooling,

so that the temperature does not surpass 50 C. 80 parts of oleum of the same strength are added and, in'order to avoid a momentary violent reaction of the mixture kept at room temperature,

the double decomposition is performed in several 40 portions by warming them on the water bath, while stirring, whereupon after a short time a vivid evolution of gas begins with separation or 1 amino sulphonic acid;- When the reaction ceases,

a further portion of the aforesaid mixture is added and this sequence oi reactions is continued until the whole mass is consumed. 'I'henthe amino sulphonic acid is separatedas described in the foregoing examples.

The yield of amino sulphonic acid depends upon the SO: content of the fuming sulphuric acid, is improved with a higher content of S0: and becomes-nearly quantitative ii the SO: content corresponds (cf. the second formula given above) to about 45 per cent, that is, to the pyrol6 sulphonic acid. The temperature at which the double decomposition is performed may be lowered in the case of a higher SO: content of the reacting acid.

Example 5.-30 parts of urea are dissolved in sulphuric acid.

2. The process for producing amino sulphonic acid which comprises introducing urea into concentrated sulphuric acid and adding fuming sulphuric acid.

3. The process for producing amino sulphonic PAUL BAUMGARTEN.

CERTIFICATE OF I CORRECTION.

Patent No 2,102, 550.

acid which comprises introducing urea into cooled 6 50 parts by volume of sulphuric acid of 100 per fuming sulphuric acid and thereupon warming cent. strength and to this solution are added at a the mixture. temperature of about 40 C. 75 parts by volume of 4. The process for producing amino sulphonic oieum containing '20 per cent. of $01. On warmacid which comprises dissolving urea in concen- 10 ing this mixture in portions'on the water bath, 93 trated sulphuric acid, adding oieum containing 70 10 parts of crude amino sulphonic acid are obtained per cent. of S03, and warming the mixture. containing 96.4 per cent. of NH: SOaH, i. e.. the 5. Process for preparing sulphamic acid which yield is 92.4 per cent. of the theoretical amount comprises reacting urea with oieum. calculated on urea. When using 90 parts by 6. Process for preparing sulphamic acid which 15 weight instead of 75 parts of oieum of 70 per cent. comprises dissolving urea in concentrated sul- 15 strength, the yiel". calculated on pure amino phuric acid and reacting theresulting solution sulphonic acid and on the urea, is 94 per cent. with oieum.

What I claim is: v '1. The process for producing amino sulphonic l. The process for producing amino sulphonic acid which comprises reacting urea with sulphur 20 acid which comprises reacting urea with fuming trioxide in the presence of sulphuric acid. 20

December 11. 19357.

PAUL BAUMGARTEN.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows Page 1, second column, line 1 .5, for the word "vivid" read violent; and that the said Lettars-Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 22nd day of February, A. D. 1958.

(Seal) Henry Van Arsdale Acting Commissioner of Patents.

sulphonic acid. The temperature at which the double decomposition is performed may be lowered in the case of a higher SO: content of the reacting acid.

Example 5.-30 parts of urea are dissolved in sulphuric acid.

2. The process for producing amino sulphonic acid which comprises introducing urea into concentrated sulphuric acid and adding fuming sulphuric acid.

3. The process for producing amino sulphonic PAUL BAUMGARTEN.

CERTIFICATE OF I CORRECTION.

Patent No 2,102, 550.

acid which comprises introducing urea into cooled 6 50 parts by volume of sulphuric acid of 100 per fuming sulphuric acid and thereupon warming cent. strength and to this solution are added at a the mixture. temperature of about 40 C. 75 parts by volume of 4. The process for producing amino sulphonic oieum containing '20 per cent. of $01. On warmacid which comprises dissolving urea in concen- 10 ing this mixture in portions'on the water bath, 93 trated sulphuric acid, adding oieum containing 70 10 parts of crude amino sulphonic acid are obtained per cent. of S03, and warming the mixture. containing 96.4 per cent. of NH: SOaH, i. e.. the 5. Process for preparing sulphamic acid which yield is 92.4 per cent. of the theoretical amount comprises reacting urea with oieum. calculated on urea. When using 90 parts by 6. Process for preparing sulphamic acid which 15 weight instead of 75 parts of oieum of 70 per cent. comprises dissolving urea in concentrated sul- 15 strength, the yiel". calculated on pure amino phuric acid and reacting theresulting solution sulphonic acid and on the urea, is 94 per cent. with oieum.

What I claim is: v '1. The process for producing amino sulphonic l. The process for producing amino sulphonic acid which comprises reacting urea with sulphur 20 acid which comprises reacting urea with fuming trioxide in the presence of sulphuric acid. 20

December 11. 19357.

PAUL BAUMGARTEN.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows Page 1, second column, line 1 .5, for the word "vivid" read violent; and that the said Lettars-Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 22nd day of February, A. D. 1958.

(Seal) Henry Van Arsdale Acting Commissioner of Patents. 

